A tool holder for clamping the shank of a tool is known from European patent application EP 2 266 732 A1 (see FIG. 5). This tool holder has a clamping wedge provided with spiral ribs that engage with a helical groove of a collet. In order to clamp a tool shank, the clamping wedge and the tool that is to be clamped first have to be joined together and then, as a unit, screwed to the collet. Moreover, a certain amount of play between the ribs of the clamping wedge and the groove of the collet has to be compensated for by means of a screw bolt that acts in the axial direction. All in all, the clamping of a tool is relatively laborious and very time-consuming.
Furthermore, a drawback of European patent application EP 2 266 732 A1 is that the collet and the clamping wedge have to be provided with thread elements (ribs and grooves) that are relatively complex to manufacture, which is associated with a correspondingly high production effort.
An advantage of the tool holder known from European patent application EP 2 266 732 A1 is the possibility to use standardized tools, especially tools with a lateral drive flat that complies with DIN 1835-1, Form B. Such drive flats are also known by the name “Weldon surfaces” and, in the simplest case, they constitute part of an anti-twist protection of a tool in a Weldon chuck, whereby the Weldon surface of the tool serves as a counter-surface for the end face of a self-locking bolt that goes through the Weldon chuck.